From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E9E0C433ED for ; Sat, 10 Apr 2021 14:01:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54C2F610A7 for ; Sat, 10 Apr 2021 14:01:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234513AbhDJOCD (ORCPT ); Sat, 10 Apr 2021 10:02:03 -0400 Received: from forward3-smtp.messagingengine.com ([66.111.4.237]:35381 "EHLO forward3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234392AbhDJOCB (ORCPT ); Sat, 10 Apr 2021 10:02:01 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailforward.nyi.internal (Postfix) with ESMTP id B14441940AB9; Sat, 10 Apr 2021 10:01:46 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Sat, 10 Apr 2021 10:01:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=gTMkEW FZIzW+U3x2gs7wM1UZYZd3f5yxeYdKlGDyklI=; b=YISffvUJ/SZo8tA76Obi6J fQllIym4oYx6RmIyZxptKeXbAHoOcf9+WT8DcIRK9WuJCtqriYVtpIt8hAnTqhGw iQvaEOAi5X52/4xdWgA2a8dLW+rGBzORIwE4OgzGWqNODlyAOctEgh+EiD8IIq2F TiNcnX1iz6Pa0PziSyEGy6bhO+KlamY6OUr0IbodWXSiGxaXQ1l64/oxNZAjq60N +XziMXMwX3tyClH1mFM8n0PMuhlMVdxXPktrIHQzlm8OZgMWV7LOB8TsMkLuPMnF ezI50I67wgm7DYLiwKRj3sx89vNj6bj25aIzUuZgmq2/AVbNvJR/wricbnlmw7ZQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrudekfedgjedvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepieetveehuedvhfdtgfdvieeiheehfeelveevheejud etveeuveeludejjefgteehnecukfhppeekfedrkeeirdejgedrieegnecuvehluhhsthgv rhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorghhrd gtohhm X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id 6F0DF240054; Sat, 10 Apr 2021 10:01:45 -0400 (EDT) Subject: FAILED: patch "[PATCH] net: hso: fix null-ptr-deref during tty device unregistration" failed to apply to 4.14-stable tree To: mail@anirudhrb.com, davem@davemloft.net, gregkh@linuxfoundation.org Cc: From: Date: Sat, 10 Apr 2021 16:01:43 +0200 Message-ID: <161806330327108@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8a12f8836145ffe37e9c8733dce18c22fb668b66 Mon Sep 17 00:00:00 2001 From: Anirudh Rayabharam Date: Wed, 7 Apr 2021 22:57:22 +0530 Subject: [PATCH] net: hso: fix null-ptr-deref during tty device unregistration Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref. The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number. Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call. Fixes: 72dc1c096c705 ("HSO: add option hso driver") Reported-by: syzbot+c49fe6089f295a05e6f8@syzkaller.appspotmail.com Tested-by: syzbot+c49fe6089f295a05e6f8@syzkaller.appspotmail.com Reviewed-by: Greg Kroah-Hartman Signed-off-by: Anirudh Rayabharam Signed-off-by: David S. Miller diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c index 31d51346786a..9bc58e64b5b7 100644 --- a/drivers/net/usb/hso.c +++ b/drivers/net/usb/hso.c @@ -611,7 +611,7 @@ static struct hso_serial *get_serial_by_index(unsigned index) return serial; } -static int get_free_serial_index(void) +static int obtain_minor(struct hso_serial *serial) { int index; unsigned long flags; @@ -619,8 +619,10 @@ static int get_free_serial_index(void) spin_lock_irqsave(&serial_table_lock, flags); for (index = 0; index < HSO_SERIAL_TTY_MINORS; index++) { if (serial_table[index] == NULL) { + serial_table[index] = serial->parent; + serial->minor = index; spin_unlock_irqrestore(&serial_table_lock, flags); - return index; + return 0; } } spin_unlock_irqrestore(&serial_table_lock, flags); @@ -629,15 +631,12 @@ static int get_free_serial_index(void) return -1; } -static void set_serial_by_index(unsigned index, struct hso_serial *serial) +static void release_minor(struct hso_serial *serial) { unsigned long flags; spin_lock_irqsave(&serial_table_lock, flags); - if (serial) - serial_table[index] = serial->parent; - else - serial_table[index] = NULL; + serial_table[serial->minor] = NULL; spin_unlock_irqrestore(&serial_table_lock, flags); } @@ -2230,6 +2229,7 @@ static int hso_stop_serial_device(struct hso_device *hso_dev) static void hso_serial_tty_unregister(struct hso_serial *serial) { tty_unregister_device(tty_drv, serial->minor); + release_minor(serial); } static void hso_serial_common_free(struct hso_serial *serial) @@ -2253,24 +2253,22 @@ static void hso_serial_common_free(struct hso_serial *serial) static int hso_serial_common_create(struct hso_serial *serial, int num_urbs, int rx_size, int tx_size) { - int minor; int i; tty_port_init(&serial->port); - minor = get_free_serial_index(); - if (minor < 0) + if (obtain_minor(serial)) goto exit2; /* register our minor number */ serial->parent->dev = tty_port_register_device_attr(&serial->port, - tty_drv, minor, &serial->parent->interface->dev, + tty_drv, serial->minor, &serial->parent->interface->dev, serial->parent, hso_serial_dev_groups); - if (IS_ERR(serial->parent->dev)) + if (IS_ERR(serial->parent->dev)) { + release_minor(serial); goto exit2; + } - /* fill in specific data for later use */ - serial->minor = minor; serial->magic = HSO_SERIAL_MAGIC; spin_lock_init(&serial->serial_lock); serial->num_rx_urbs = num_urbs; @@ -2667,9 +2665,6 @@ static struct hso_device *hso_create_bulk_serial_device( serial->write_data = hso_std_serial_write_data; - /* and record this serial */ - set_serial_by_index(serial->minor, serial); - /* setup the proc dirs and files if needed */ hso_log_port(hso_dev); @@ -2726,9 +2721,6 @@ struct hso_device *hso_create_mux_serial_device(struct usb_interface *interface, serial->shared_int->ref_count++; mutex_unlock(&serial->shared_int->shared_int_lock); - /* and record this serial */ - set_serial_by_index(serial->minor, serial); - /* setup the proc dirs and files if needed */ hso_log_port(hso_dev); @@ -3113,7 +3105,6 @@ static void hso_free_interface(struct usb_interface *interface) cancel_work_sync(&serial_table[i]->async_get_intf); hso_serial_tty_unregister(serial); kref_put(&serial_table[i]->ref, hso_serial_ref_free); - set_serial_by_index(i, NULL); } }